A kuo-toa superficially resemble a grotesque cross between a fish and a humanoid. Their stout, stocky bodies are covered in slippery blue or purple scales, with clawed, webbed feet and black nails. Their hands are much more human-like, ending in the blunt nails typical of most humanoid races. Where one would normally expect the neck of a humanoid to be, there is instead the head of a fish, placed as if it had been grafted on. Some kuo-toa will display whiskers similar to those of a catfish, others have fins at the sides or tops of their heads, and a few have a mixture of both. Their bulging eyes are always a sickly yellow color, with a massive black pupil in the center.

In days long past, kuo-toa once dwelled on the shores and islands of the surface world. The kuo-toa were driven deep underground by the humans and their ilk, dooming them to spend eternity in darkness. In their prison of the Underdark, the kuo-toa came into contact with the illithid, and found themselves a new set of oppressors. The illithid subjected the kuo-toa to slavery, condemning thousands to lives as chattel. The kuo-toa were a simple race, and were never intended to bear through the mental strain the illithids' psychic energy placed upon them. Nearly every kuo-toa was driven hopelessly mad and paranoid, and they retain their madness, even long after the mind flayers abandoned them. They invent their own gods in their madness, in a vain effort to protect themselves from the threats they face in their dangerous home.

Kuo-toa revere deities of their own design. Though their gods are not real, if enough kuo-toa fervently believe in a deity, their subconcious minds have a strange way of combining their power and manifesting that deity as a physical entity. Among the most revered kuo-toa gods are Blibdoolpoolp the Sea Mother, a female human with a crayfish head, claws, and shell covering her shoulders.
Archpriests hold among the highest positions in kuo-toa society, being surrounded by fanatical devotees of their faith. Archpriests' devotion to their deity is so fervent that they manifest divine powers similar to a cleric. Archpriests also have the power to bestow a fraction of their mystical powers to particularly loyal underlings known as whips, who fight to the death to become the archpriest's heir when the archpriest succumbs. A disloyal whip may be stripped of its powers, if not its life.
Most other humanoid societies view the kuo-toas' strange ways with disdain, chief among them being the Drow, who have slain the kuo-toa on sight as long as the two races have known each other.

A repugnant race of slimy fish-like humanoids.Ability Score Increase. Your Strength score increases by 2, and your Wisdom score increases by 1.Age. The Kuo-toa age a bit faster than humans, reaching maturity at age 7 and living around half a century.Alignment. Kuo-toa generally tend towards evil, their insane minds feeding their primal selfishness.Size. Kuo-toa range from a little over 4 and a half to just barely over 5 feet tall, and weigh on average 120 pounds. Your size is Medium.Speed. Your base walking speed is 30 feet, and you have a swimming speed of 30 feet.Amphibious. You can breathe in both air and water.Darkvision. You are accustomed to the darkness of the Underdark, where daylight has no power. You can see in dim light within 120 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.Slippery. You have advantage on ability checks and saving throws made to escape a grapple.Sunlight Sensitivity. You have disadvantage on attack rolls and Wisdom (Perception) checks that rely on sight when you, the target of your attack, or whatever you are trying to perceive is in direct sunlight.Otherworldly Perception. As an action, you can choose to glimpse beyond the veil of reality for a brief window of time. For the next minute, you can see invisible creatures and objects within 60 feet of you as if they were visible, and you can see 60 feet into the Ethereal Plane. Once you use this trait, you cannot do so again until you finish a long rest.Languages. You can speak, read, and write Common and Undercommon.